enhance: add metrics for restful apis

[PowderLi]

issue: #34968
pr: #34969

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[codecov]

Codecov Report

Attention: Patch coverage is 82.60870% with 4 lines in your changes missing coverage. Please review.

Project coverage is 81.07%. Comparing base (cc188fb) to head (75cb6b9).
Report is 1 commits behind head on 2.4.

Additional details and impacted files

@@            Coverage Diff             @@
##              2.4   #35083      +/-   ##
==========================================
- Coverage   81.10%   81.07%   -0.04%     
==========================================
  Files        1051     1051              
  Lines      136692   136714      +22     
==========================================
- Hits       110870   110842      -28     
- Misses      21620    21654      +34     
- Partials     4202     4218      +16     

Files	Coverage Δ
pkg/metrics/metrics.go	100.00% <ø> (ø)
pkg/metrics/proxy_metrics.go	100.00% <100.00%> (ø)
internal/distributed/proxy/service.go	83.97% <78.94%> (-0.17%)	⬇️

... and 24 files with indirect coverage changes

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[czs007]

/approve
/lgtm

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